Ferro device for the automatic control of x-y displacements in x-ray examination

ABSTRACT

An X-ray radiating apparatus which includes an automatic device for controlling the simultaneous displacements of the radiating and recording parts of the apparatus, the device comprising a platform adapted to revolve with constant angular speed, along a diameter of which is displaced a finger driving parallelograms holding the apparatus and various coding members corresponding to the curves to be traced. The actuation of a coder determines the displacements of the finger.

United States Patent 1191 Rouge 1 1 Feb. 12, 1974 1 FERRO DEVICE FOR THEAUTOMATIC 2,885,618 5/1959 Belsteringnt 318/579 x CONTROL OFDISPLACEMENTS [N 3,039,035 6/1962 Rudolf, Jr. et a1 318/579 3,136,9366/1964 Eisengrein 1 318/579 X-RAY EXAMINATION 3,174,089 3/1965 Hawkinset a1... 318/579 [75] Inventor: Serge Rouge, Montrouge, France 3,573,5864/1971 Littwin v 318/579 3,700,994 10/1972 Gopfert 318/579 [73]Ass1gnee: U.S. Philips Corporation, New

York, N.Y. Y [22] Filed: g 1972 Prtmary Exammer-T. E. Lynch Appl.1\1o.:281,343

Related U.S.-Application Data Continuation of Ser. No. 17,392, March 9,1970, abandoned.

Attorney, Agent, or FirmFrank R. Trifari 8 Claims, 10 Drawing FiguresPATENIEUFEB12 I974 3,792,334

sum 3 a? 9 FiBc INVENTOR. SK-Rz; 00 66 FERRO DEVICE FOR THE AUTOMATICCONTROL OF X-Y DISPLACEMENTS IN X-RAY EXAMINATION This is acontinuation, of application Ser. No. 17,392, filed Mar. 9, 1970 nowabandoned.

This invention in the domain of X-ray technology applied to medicaldiagnostics, and relates to a device for the automatic control ofsimultaneous displacements of the X-ray analysing and recordingapparatus, particularly for X-ray examination in sections termedradiographs.

When the pivotal axis of these apparatus is located in the plane of thesection, the analysing apparatus (X-ray tube) and the recordingapparatus (film cassette), held by identical parallelograms can describevarious curves such as straight lines, circles, ellipses, hypocycloids.

The control-boxes usually employed with these apparatus do not permit ofcontrolling automatically the changes of the curves. These boxes havevarious openings corresponding to the various curves and any change ofthe curve is obtained by the manual displacement of a stub screwed inthe corresponding box opening, i.e., straight lines and ellipses (bymeans of stubs of different lengths in the same opening), hypocycloids,small circles.

Moreover, various proposals based on a decomposition of the variouscurves into given Cartesian coordinates lead to complicated embodiments,especially in the case of a hypocycloid.

The invention provides a'novel control-device operating completelyautomatically and permitting of carrying out changes of curves from adistance and of restoring automatically in a simple manner the restposition.

According to the invention the control-device comprises a control-boxfor the various displacements operating by means of an electronicassembly, which is controlled by taking into circuit two variableelements, one for said displacements and the other selected from anassembly of elements coding the various curves, said electronic assemblyoperating so that at any instant the voltages across the two variableelements are equal to each other.

Other featuresof the invention and the preferred embodiment thereof willbe apparent from the following description given by way of example withreference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view of theupper part of a control-box according to the invention,

FIG. 2 is a schematic bottom view of the control-box,

FIG. 3 a side elevation of the same box,

FIG. 4 the circuit diagram of the electronic assembly controlling themovements of the box,

FIGS. 5a, 5b, Be a cam profile and the decompositions of the ellipticcurve into polar data;

FIGS. 6a, 6b, 60 a further cam profile and the decompositions of thehypocycloid curve into polar data.

DESCRIPTION OF THE PREFERRED EMBODIMENT The device according to theinvention is based on the principle of decomposing the curves into polardata. For the sake of clarity the device will first be described andafterwards the operation will be specified in accordance with thevarious curves (in this example: straightline, circle, ellipse,hypocycloid).

The device comprises a box controlling the various movements by means ofan electronic assembly, which is controlled from a panal by taking intocircuit variable elements forming part of the box and/or beingindependent. The control-box, which forms a characteristic part of thedevice, will be described hereinafter with reference to FIGS. 1, 2 and3, and the basic circuitry of the electronic assembly for thespecification of the various curves will be explained with reference toFIG. 4 in order to facilitate a good understanding of the operation ofsaid box.

As shown in FIGS. 1 and 3, box comprises a platform carried by asupporting frame 21, adapted to be driven electrically with a constantangular speed by a belt C transmitting the movement by an external motor(not shown). The device is arranged so that a choice can be made from arange of speeds.

Over a diameter of the platform 21 formed by a support 211, a finger 22is displaceable to perform the necessary displacement of the X-ray tubeand the film cassette. The finger 22 is held by a carriage 221,accurately guided and pushed over a set of rails 222, which transmit tothe carriage 221 the movement of a motor 223 (axis X X) via a reducingmechanism 224. In this way it is possible to move the finger 22 at anyinstant into any position previously defined on the diameter concerned.Two safety stop members are indicated at 229 on the platform.

The successive positions of the finger determine the curvessimultaneously described by the X-ray tube and the cassette holder.

On the rotating platform any position of the finger 22 is converted intoan electric magnitude A by a potentiometer 225, driven by a toothed belt226 during the movement of the finger 22. These successive positions areautomatically controlled by means of a coding member 230, of the codersof which is actuated, when a curve differing from a straight line or acircle has to be obtained, which curve requires suitable combinations ofthemovements. In the example described the coding member is designed fortwo curves i.e., hypocycloid curve and elliptic curve. The coders may beformed by rotatable potentiometers, the tappings of which occupyrespectively a position depending upon the positions of cams turnedaround the axis ZZ' by means of a transmission belt 24 which may bedriven by a motor not shown, or by motor 233.

FIG. 2, which illustrates schematically a bottom view of the box, showsone of the coders. The cam 231, whose profile matches, for example, theellipse, is adapted to rotate about the vertical axis ZZ. A sensor 232which follows up the cam profile, is associated with the rotatablepotentiometer 233, driven by a gear wheel 234 which cooperates with atoothed rack 235 on a rod 236, associated with a spring 237.

Hereinafter 233E and 233H will designate the ellipse and the hypocycloidrespectively. The variation of the radius of the cam is thus convertedinto a variation of the position of the tapping (not shown) of thepotentiometer; to this position of the tapping corresponds an electricmagnitude B.

The control-device according to the invention performs the movement sothat at any instant the difference between the two electric magnitudes Aand B approaches zero as closely as possible, said two electricmagnitudes (e.g., voltages) being applied to the terminals of theelectronic assembely 31 (FIG. 4), which control the rotation of themotor 223 the difference be tween said two magnitudes constituting acontrol signal.

For this purpose the electronic assembly 31 is connected on the one handto the potentiometer 225 and on the other hand in accordance with one ofthe four positions of the switch 41 (on the control-panel) to one of thefour follwing elements:

potentiometer 233H for the'hypocycloid curve,

potentiometer 233E for the elliptic curve,

capacitor 411,

potentiometer 412. The latter two elements are external of thecontrol-box.

Therefore the control-box (FIG. 3) is provided with a multiple input 227for the electric connections such as 228 comprising, for example, twowires for the wind- .ing of the motor 223, three wires for thecontrol-potentiometer, three safety wires.

By the combination of the two movements of rotation with constant speedand of linear displacement of the finger as controlled by the electronicassembly, the

control-device describe above permits of describing in a simple mannerthe following curves:

1. a circle: by the rotation of the platform 21 with constant speed; acircle of variable. radius in accordance with the position of the finger22 on a diameter of the platform can be obtained by manual actuation ofthe potentiometer 412 on the control-panel;

2. a straight line: by the linear displacement of the finger 22 underthe control of the capacitor 411 the slope of the straight line is afunction of the voltage of the capacitor; moreover, by revolving theplatform 21 by the manual displacement of the potentiometer 412 thestraigh line can be orientated;

3. ellipse: referring to FIGS. 5a, 5b, 5c by the combination of the twomovements, while the electronic assembly 31 is connected 'to thepotentiometer 23313.

The movement of the finger 22 is then transmitted to the ellipticposition coder, the cam profile of which is shown in FIG. 5a; thedecomposition into polar coordinates of the elliptic curve isillustrated in FIGS. 5b and 5c.

4. Hypocycloid: referring to FIGS. 6a, 6b and 60, by the combination ofthe two movements, while the electronic assembly 31 is connected to thepotentiometer 233H. The movement of the finger 22 is then transmitted tothe hypocycloid position coder.

5. It is also possible to obtain a spiral passing through the centre andreturning through its extremity by the consecutive use of the twomovements: the rotation of the platform during the preparation of theX-ray photograph to which is added alinear displacement of the fingersolely during the X-ray exposure (connection to the capacitor 411).

Moreover, in static operation the movement of the finger is controlledby the positioning potentiometer 412, which allows centering orinclination of the radiation. By a slow revolutionof the platform theplane of radiation may be changed relatively to the longitudinal axis ofthe analysing table (not shown).

The invention is not limited to the example described above and withinthe scope of the invention modifications may be carried out, forexample, in the number and the shape of the cams and in the fingerdriving mechanism. Moreover, the changes of orientation may be obtainedby an angular displacement of the cams.

The invention is particularly suitable in tomography, since it allow arapid and simple control of the orientation of the various exposures.

What is claimed is:

1. In an apparatus for controlling the movement of an x-ray radiatingassembly which includes an x-ray source and a film cassette which arearranged to be displaceable in relatively opposite directions andare'adapted to swing about a pivotal axis for making radiographs ofplane body sections, wherein an x-ray passing through any point to beradiographed will always strike the same point at the film, theapparatus further including a control assembly comprising, a rotatableplatform, first means for rotating said platform, a guide member carriedand rotated by the platform and movable longitudinally on said platform,the guide member adapted to displace said x-ray tube and film cassetteaccording to a predetermined cycle including rotational and longitudinalmovement, second means for driving ,said guide member in longitudinalmovement on said platform, a first potentiometer on said platformengaged and driven by said guide member for converting each position ofsaid guide member into a first electrical signal corresponding to itsmovement, a rotatable camcoding member carried by the assembly, this camhaving a cam-shape to provide said predetermined cycle of movement,means for rotating the cam, a cam follower driveable in longitudinalmovement by said cam, a second potentiometer driven by said follower forconverting displacement of the follower into a second electric signalhaving magnitude corresponding to the camshape and to the distance theguide member is to move, third means for comparing the first signal withthe second signal and producing the profile signal corresponding to thedifference between said signals, said control signal being communicatedto said second means to move said guide member longitudinally until thefirst and second signals are equal and there is no difference betweenthese signals.

2. Apparatus according to claim 1 wherein said platform rotates at aconstant angular speed, and said movable member is arranged at saidplatform for movement along a diameter thereof.

3. Apparatus according to claim 2 further comprising a cam rotating withconstant speed corresponding to the rotation of the platform foroperating said coding member, th rofile of the cam being a function ofthe curve to be traced.

4. In an apparatus for controlling the movement of an x-ray radiatingassembly which includes an x-ray source and a film cassette which arearranged to be displaceable in relatively opposite directions and areadapted to swing about a pivotal axis for making radiographs of planebody sections, whereby an x-ray passing through any point to beradiographed will always strike the same point at the film, theapparatus further including a control assembly comprising, a rotatableplatform, first means for rotating said platform, a guide member carriedand rotated by the platform and movable longitudinally on said platform,the guide member adapted to displace said x-ray tube and film cassettein both rotational and longitudinal movement, second means for drivingsaid guide member in longitudinal movement on said platform, sensingmeans for sensing the longitudinal position of said guide memberand forproviding a first electric signal corresponding to said position, afunction generator for providing a second electric signal correspondingto a desired predetermined longitudinal motion of said guide member,means for comparing the first signal with the second signal andproducing a control signal corresponding to the difference between saidfirst and second signals, said control signal being communicated to saidsecond means to move said guide member longitudinally until the firstand second signals are equal and there is no difference between thesesignals.

5. Apparatus according to claim 4 wherein said function generatorcomprises a potentiometer for providing a constant voltage signal ofmanually selectable magnitude.

6. Apparatus according to claim 5 wherein said function generatorfurther comprises a rotatable camcoding member carried by the assembly,the cam having a cam-shape to provide said predetermined motion, meansfor rotating the cam, a cam follower drivable in longitudinal movementby the cam, a second potentiometer driven by said follower forconverting displacement of the follower into the second electric signalhav.- ing magnitude corresponding to the cam shape and to the distancethe guide member is to move.

7. Apparatus according to claim 4 wherein said function generatorcomprises a capacitor, means for supplying constant voltage to thecapacitor, and means for discharging said capacitor.

8. In an apparatus for controlling the movement of an x-ray radiatingassembly which includes an x-ray source and a film cassette which arearranged to be displaceable in relatively opposite directions and areadapted to swing about a pivotal axis for making radiographs of planebody sections, whereby an x-ray passing through any point to beradiographed will always strike the same point at the film, theapparatus further including a control assembly comprising, a rotatableplatform, first means for rotating said platform, a guide member carriedand rotated by the platform and movable longi' tudinally on saidplatform, the guide member adapted to displace said x-ray tube and filmcassette in both rotational and longitudinal movement, second means fordriving said guide member in longitudinal movement on said platform,sensing means for sensing the longitudinal position of said guide memberand for providing a first electric signal corresponding to saidposition, a function generator for providing a second electric signalcorresponding to adesired predetermined longitudinal motion of saidguide member said function generator comprising means for providing aplurality of different electric signals as said second signal, switchmeans for selecting one of said plurality of signals, means forcomparing the first signal with the second signal and producing acontrol signal corresponding to the difference between said first andsecond signals, said control signal being communicated to said secondmeans to move said guide member longitudinally until the first andsecond signals are equal and there is no difference between thesesignals.

UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTIONPATENT NO. 3,79 3% DATED Feb. 12, 1974 INVENTOR(S) SERGE ROUGE ltiscertified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below:

In the title, "FERRO" should be --SERVO- Column 2, line 14, after "3,"insert -the--;

after "platform" insert -2lline 15, delete "21" Signed and Scaled thisAttest: I

RUTH C. MASON C. MARSHALL DANN Arresting Officer Commissioner of Patentsand Trademarks UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OFCORRECTION PATENT NO. 3,792,554

DATED Feb. 12, 1974 mvmrorus) SERGE ROUGE ltis certified that errorappears in the above-identified patent and that said Letters Patent arehereby corrected as shown below:

In the title, "FERRO" should be -SERVO Column 2, line 14, after "3,"insert --the-;

after "platform" insert -2lline 15, delete "2l" Signed and Scaled thisFourth D3) of January 1977 [SEAL] Arrest:

RUTH C. MASON C. MARSHALL DANN A! I 8 17 Commissioner oj'Palents andTrademarks

1. In an apparatus for controlling the movement of an x-ray radiatingassembly which includes an x-ray source and a film cassette which arearranged to be displaceable in relatively opposite directions and areadapted to swing about a pivotal axis for making radiographs of planebody sections, wherein an x-ray passing through any point to beradiographed will always strike the same point at the film, theapparatus further including a control assembly comprising, a rotatableplatform, first means for rotating said platform, a guide member carriedand rotated by the platform and movable longitudinally on said platform,the guide member adapted to displace said x-ray tube and film cassetteaccording to a predetermined cyCle including rotational and longitudinalmovement, second means for driving said guide member in longitudinalmovement on said platform, a first potentiometer on said platformengaged and driven by said guide member for converting each position ofsaid guide member into a first electrical signal corresponding to itsmovement, a rotatable cam-coding member carried by the assembly, thiscam having a cam-shape to provide said predetermined cycle of movement,means for rotating the cam, a cam follower driveable in longitudinalmovement by said cam, a second potentiometer driven by said follower forconverting displacement of the follower into a second electric signalhaving magnitude corresponding to the cam-shape and to the distance theguide member is to move, third means for comparing the first signal withthe second signal and producing the profile signal corresponding to thedifference between said signals, said control signal being communicatedto said second means to move said guide member longitudinally until thefirst and second signals are equal and there is no difference betweenthese signals.
 2. Apparatus according to claim 1 wherein said platformrotates at a constant angular speed, and said movable member is arrangedat said platform for movement along a diameter thereof.
 3. Apparatusaccording to claim 2 further comprising a cam rotating with constantspeed corresponding to the rotation of the platform for operating saidcoding member, th rofile of the cam being a function of the curve to betraced.
 4. In an apparatus for controlling the movement of an x-rayradiating assembly which includes an x-ray source and a film cassettewhich are arranged to be displaceable in relatively opposite directionsand are adapted to swing about a pivotal axis for making radiographs ofplane body sections, whereby an x-ray passing through any point to beradiographed will always strike the same point at the film, theapparatus further including a control assembly comprising, a rotatableplatform, first means for rotating said platform, a guide member carriedand rotated by the platform and movable longitudinally on said platform,the guide member adapted to displace said x-ray tube and film cassettein both rotational and longitudinal movement, second means for drivingsaid guide member in longitudinal movement on said platform, sensingmeans for sensing the longitudinal position of said guide member and forproviding a first electric signal corresponding to said position, afunction generator for providing a second electric signal correspondingto a desired predetermined longitudinal motion of said guide member,means for comparing the first signal with the second signal andproducing a control signal corresponding to the difference between saidfirst and second signals, said control signal being communicated to saidsecond means to move said guide member longitudinally until the firstand second signals are equal and there is no difference between thesesignals.
 5. Apparatus according to claim 4 wherein said functiongenerator comprises a potentiometer for providing a constant voltagesignal of manually selectable magnitude.
 6. Apparatus according to claim5 wherein said function generator further comprises a rotatablecam-coding member carried by the assembly, the cam having a cam-shape toprovide said predetermined motion, means for rotating the cam, a camfollower drivable in longitudinal movement by the cam, a secondpotentiometer driven by said follower for converting displacement of thefollower into the second electric signal having magnitude correspondingto the cam shape and to the distance the guide member is to move. 7.Apparatus according to claim 4 wherein said function generator comprisesa capacitor, means for supplying constant voltage to the capacitor, andmeans for discharging said capacitor.
 8. In an apparatus for controllingthe movement of an x-ray radiating assembly which includes an x-raysource and a film cassette which are arranged tO be displaceable inrelatively opposite directions and are adapted to swing about a pivotalaxis for making radiographs of plane body sections, whereby an x-raypassing through any point to be radiographed will always strike the samepoint at the film, the apparatus further including a control assemblycomprising, a rotatable platform, first means for rotating saidplatform, a guide member carried and rotated by the platform and movablelongitudinally on said platform, the guide member adapted to displacesaid x-ray tube and film cassette in both rotational and longitudinalmovement, second means for driving said guide member in longitudinalmovement on said platform, sensing means for sensing the longitudinalposition of said guide member and for providing a first electric signalcorresponding to said position, a function generator for providing asecond electric signal corresponding to a desired predeterminedlongitudinal motion of said guide member said function generatorcomprising means for providing a plurality of different electric signalsas said second signal, switch means for selecting one of said pluralityof signals, means for comparing the first signal with the second signaland producing a control signal corresponding to the difference betweensaid first and second signals, said control signal being communicated tosaid second means to move said guide member longitudinally until thefirst and second signals are equal and there is no difference betweenthese signals.